Manchester, New Hampshire (CNN)As Jeb Bush plows ahead to South Carolina following his better-than-expected New Hampshire primary finish, George W. Bush is hitting the radio waves on behalf of his younger brother.

"Jeb has dealt with crises as the governor of Florida, and he did so with steadiness, and a calmness necessary in a good leader," the former president says in the ad, which begins airing in South Carolina on Wednesday.

George W. Bush has lent his name to fundraising emails and appeared at fundraisers for the campaign, and most recently he starred in a TV ad for the pro-Bush super PAC Right to Rise USA.

But the radio ad marks the first time the 43rd president will appear in a campaign ad for Jeb Bush.

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"He respects the military -- he honors their families. He can make the tough decision to keep Americans safe and our country free. And in a time of crisis, he will be a steady hand," he says in the spot.

The ad comes ahead of George W. Bush's expected cameo on the campaign trail before next week's primary on February 20. South Carolina was a good state for both George W. Bush and his father, former President George H.W. Bush, and the campaign is hoping that touting the family name will generate some buzz.

"The Bush family name is long and deep in South Carolina," Sen. Lindsey Graham, who's now backing Jeb Bush after ending his own presidential bid, told reporters Tuesday night. "41 and 43 are well respected. The Bush family has been generations of servants. That will matter in my state."